The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon.
The present invention relates generally to firearm technology, and more particularly to a control knob assembly for rapid zeroing of a position adjusting mechanism such as those found on automatic, tripod-mounted guns.
Automatic guns mounted on tripods typically have a variety of position adjustments that must be made for proper aiming of the gun. Such position adjustments are often made using control knobs. These control knobs must often be returned to a reference or zero point once the particular adjustment is made. Thus, as used herein, zeroing involves the process of first turning a control knob some number of degrees (based on a scale that is referenced to the knob) to adjust the position of the gun and then, without changing the position of the gun, moving the scale to xe2x80x9czeroxe2x80x9d, i.e., a base or reference point.
Prior art zeroing systems typically use an incremented ring that is separate from the knob. In these systems, the ring is either moved into place against some friction after the knob is in position, or the ring is unlocked, moved, and then locked back down. Ideally, a zeroing system for a control knob should be easier and faster to use than the prior art systems.
Accordingly, it is a primary object of the present invention to provide a control knob assembly that can be easily operated to zero an automatic gun.
It is another object of the present invention to provide a control knob assembly for zeroing an automatic gun in one motion by pulling out a knob, rotating the knob to zero, and then letting the knob snap back in place without causing the gun to move.
In accordance with these and other objects, a control knob assembly includes a housing with a shaft rotatably supported therein. A ring is coupled to the shaft in such a way that rotation of the ring causes rotation of the shaft. The ring has a plurality of holes distributed therearound and extending longitudinally therethrough from a first side thereof to a second side thereof. A knob is disposed about the shaft adjacent the first side of the ring. The knob is rotatable about the shaft and slidable therealong. A spring is coupled between the knob and ring for biasing the knob towards the ring. A pin extends from the knob to engage one of the holes at the first side of the ring when the spring is free to bias the knob towards the ring. A spring-loaded detent mechanism mounted in the housing engages one of the holes from the second side of the ring. The detent mechanism permits rotation of the ring relative to the housing when the spring is free to bias the knob towards the ring. However, the detent mechanism inhibits rotation of the ring relative to the housing when the spring""s bias is overcome by a pulling force that causes the pin to disengage from one of the holes at the first side of the ring.
In a particular application of the invention, a control knob assembly is provided that may be generally used for rapid zero adjustment of a dial thereof as is particularly required for the rapid zeroing of a traverse and elevating mechanism of an automatic gun. In one embodiment, the control knob assembly provides for rapid zeroing without altering the actual position of the mechanism in which it is employed. The mechanism has a shaft with a ring formed therein having a first opening. The shaft has first and second ends. The second end of the shaft has coupling means for coupling to an automatic gun. The control knob assembly comprises a knob, a spring, a pin, and retaining means. The knob has an interior with first, second and third cutouts each having predetermined dimensions. The knob has a second opening dimensioned to be complementary to the first opening and the first cutout is dimensioned so as to accept the insertion of the ring of the shaft. The spring has first and second ends and is dimensioned for insertion into both of the first and second cutouts. The pin is inserted into both of the openings of the knob and the ring. The retaining means abuts against and holds the spring in the first and second cutouts.